Radio communication systems, such as cellular systems (e.g., spread spectrum systems such as Code Division Multiple Access (CDMA) networks), or Time Division Multiple Access (TDMA) networks), provide users with the convenience of mobility along with a rich set of services and features. This convenience has spawned significant adoption by an ever growing number of consumers as an accepted mode of communication for business and personal uses. To promote greater adoption, the telecommunication industry, from manufacturers to service providers, has agreed at great expense and effort to develop standards for communication protocols that underlie the various services and features. One area of service has received significant attention, that of Push-to-Talk over Cellular (PoC). Traditional approaches have not provided for adequate indication of a user's availability within the network.
Push-To-Talk Over Cellular (PoC) service is a two-way form of communications that allows users to engage in immediate communication with one or more users. PoC service is similar to a “walkie-talkie” application in that by pressing a button, a talk session with an individual user or broadcast group is initiated. Receiving participants hear the sender's voice either without any action on their part (auto-answer mode), or may be notified and have to accept the call (manual-answer mode) before listening to the sender's voice. Because of the “immediate” nature of this type of communication, determining presence of the user is imperative.
Therefore, there is a need for an approach for more effectively determining availability or presence information of a mobile station or user within a radio communication system.